Status : Verified
| Personal Name | John Rossmon M. Resuello |
|---|---|
| Resource Title | Sulfide Oxidation and Gold Dissolution of a Refractory Gold-Molybdenum Concentrate Using Hypochlorite Solution |
| Date Issued | 15 September 2023 |
| Abstract | The rapid depletion of easily extracted gold ores raised difficulties in using conventional cyanidation for gold extraction. Refractory gold containing gold particles locked in sulfides require pretreatment before gold leaching to achieve favorable gold recoveries. Hypochlorite (OCl-1) solution has been explored in processing refractory gold because it can oxidize the sulfides as pretreatment and dissolve gold with less impact on safety, health, and environment than cyanidation. In this study, hypochlorite solution is used for two-stage leaching of a refractory gold- molybdenum concentrate involving sulfide oxidation in the first stage and gold dissolution in the second stage. Effect of sulfide oxidation time, liquid-to-solid ratio (L:S), hypochlorite and sodium hydroxide concentrations on gold dissolution was examined. Optimization of these factors was done and reaction mechanism was inferred using the solution Eh and pH. It was observed that there is a significant increase in gold dissolution with increasing reaction time, liquid-to-solid (L:S) ratio, and OCl-1 concentration, and with decreasing sodium hydroxide (NaOH) concentration in the sulfide oxidation stage. Gold dissolution of 93.51% was achieved at oxidation of 6 hours, L:S of 13, and 1.89 M OCl-1. Molybdenum dissolution of 88.54% was also attained in this condition. In hypochlorite leaching, sulfides are oxidized by hypochlorite ions in alkaline condition in the first stage while gold is dissolved by hypochlorous acid at pH 6 in the second stage. Based on the shrinking-core model, rate-determining step for sulfide oxidation is diffusion control with an amorphous oxide forming as the product layer. Results show that the use of hypochlorite solution can be a potential eco-friendly and more simplified alternative for gold extraction of refractory gold-molybdenum concentrates. The promising gold and molybdenum dissolutions indicate that hypochlorite solution can be used to dissolve gold and molybdenum from th |
| Degree Course | MS Metallurgical Engineering |
| Language | English |
| Keyword | Hypochlorite, Refractory Gold, Green extraction |
| Material Type | Thesis/Dissertation |
Preliminary Pages
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Category : F - Regular work, i.e., it has no patentable invention or creation, the author does not wish for personal publication, there is no confidential information.
Access Permission : Open Access